1. Field of the Invention
The present invention relates to a fibrous material suitable for members used in contact with an ink, a fiber mass formed with the fibrous material, an ink tank containing the fiber mass therein, an ink-jet apparatus using the fiber mass as at least a part of its members with which an ink comes into contact, and a production process of the fibrous material.
2. Related Background Art
In ink tanks [including an ink tank portion of an ink-jet cartridge integrally formed together with an ink-jet head (recording head)] used in ink-jet (recording) apparatus, a member called an ink-absorbing member, which serves to absorb and hold an ink therein and supply the ink to a head as needed, is generally used. In one form of ink-jet cartridges and the like, in which an ink tank thereof is detachably installed in a cartridge, and the ink tank alone is replaced when an ink contained in the ink tank has been consumed, an ink-absorbing member having a joint function that strong capillary force is generated at a joint surface with a recording head to collect the ink within the ink tank there and supply it to the head, i.e., a joint member, may also be used at the same time in some cases.
As the ink-absorbing member accommodated in an ink chamber, a spongy member composed of, for example, a urethane polymer is known, while a member composed of, for example, polyethylene, polyethylene terephthal ate or the like is known as the joint member.
Since the ink-jet head has a precise structure and tends to cause ejection failure due to inclusion of dust, dirt and/or the like, it is also conducted to provide a filter at a proper position in an ink flow path in order to prevent the ejection failure.
As such ink-absorbing members (including joint members) or filters, those of various materials and forms are tried. As one of them, it is known that a fibrous material is molded at a predetermined density to attain an ink-absorbing function, joint function or filtering function making good use of spaces defined among fibers of the fibrous material.
In order to allow a molding from a fibrous material to function as an absorbing member for ink-jet inks, it is required that the ink can be effectively received by capillary force in spaces defined among fibers of the fibrous material when molded into the molding, and at the same time the spaces among the fibers are surely retained to hold the ink therein even after the ink has been charged, and that the ink can be smoothly supplied to an ink-jet head connected to the absorbing member when the pressure on the side of the head is reduced by ejection of the ink. For example, Japanese Patent Application Laid-Open No. 8-310011 discloses that a nonwoven fabric, in which a relationship between surface tension and electric conductivity satisfies a specified equation, is used as an ink-absorbing member. Japanese Patent Application Laid-Open No. 8-20115 discloses that arrangement of elastic fibers within an ink chamber of an ink tank is adjusted to surely retain spaces among the fibers, thereby allowing a molding composed of a fibrous material to function as an ink-absorbing member.
Further, a fibrous material itself requires that any component, which proves to be unfavorable to an ink itself and for the ejection of the ink from an inkjet head, is not dissolved out therefrom upon contact with the ink, or if any, its amount is reduced to an extent that such unfavorableness is not caused.
For example, Japanese Patent Application Laid-Open No. 4-348947 discloses that an ink-absorbing member composed of a urethane polymer is washed with a polar solvent in advance to dissolve and remove nonvolatile components, thereby holding down the amount of components dissolved out upon contact with an ink to at most 0.04% by weight based on the weight of the ink.
Japanese Patent Application Laid-Open No. 64-4350 has as its object the solution of a problem that additives such as metal salts of stearic acid dissolve out in an ink from a resin or synthetic rubber from which an ink tank for storing the ink is formed, and discloses the provisions of sodium ion concentration in an ink to be stored as a means for solving such a problem. However, this publication does not refer to an absorbing member for holding the ink, in particular, an absorbing member to which a fibrous material is applied, to say nothing of the production process of the fibrous material.
The present inventors have carried out an investigation in which a filamentous fibrous material of a polyolefin rein disclosed in Japanese Patent Application Laid-Open No. 8-20115 is changed to a multifilamentous fibrous material having higher productivity, or replaced by a staple fiber material, with a view toward more reducing the cost of ink-absorbing members used for ink tanks for inkjet. As a result, it has been found that the mere limitation of variation in the ratio of a surface tension to an electric conductivity before and after washing with water disclosed in Japanese Patent Application Laid-Open No. 8-310011 does not suffice materials for ink-absorbing members, and such a material may rather adversely affect printing performance in some cases.
The first cause thereof is that although attached substances which may be washed out with water have been removed from a fiber mass by washing, a part of such substances still remain in the fiber mass without being washed out. Namely, it has been found that the fact that xe2x80x9cthe ratio of the surface tension to the electric conductivity does not change even after washingxe2x80x9d referred to in Japanese Patent Application Laid-Open No. 8-310011 is unsynonymous to the fact that xe2x80x9cthe attached substances are actually removed by washingxe2x80x9d. That the attached substances remain has been clarified from the fact that there exists substances to be washed out or removed, when a fiber mass no longer undergoing a change in the ratio of the surface tension to the electric conductivity upon washing is washed out further upon dividing it into portions, which is proved by a measurement of weight change and an infrared spectroscopic spectrum analysis.
The second cause is that there are substances which cannot be removed with water and are dissolved out in an ink to adversely affect the suitability of the ink for inkjet. Namely, any treatment for removing the attached substances with water has its limit for meeting higher performance requirements even if various methods are adopted.
Further, a fibrous material itself is required not to release any component, which proves to be unfavorable to an ink itself and for the ejection of the ink from an ink-jet head, upon contact with the ink, or if any, to reduce its amount to an extent that such unfavorableness is not caused.
Japanese Patent Application Laid-Open No. 9-109410 discloses a forward contact angle necessary for a porous absorber used in the simplification and stabilization of filling of an ink into an ink-absorbing member, but neither describes nor suggests anything about an absorbing member obtained by molding fiber.
Besides, a further point to be considered includes a phenomenon described below.
Namely, there is a phenomenon that in a case where ejection energy is applied to an ink using an electrothermal converter, deposits may appear in a partial region within an ink ejection nozzle, which is distant from the electrothermal converter, not close to the electrothermal converter, in some cases, and wettability such as forward contact angle or backward contact angle with the ink in this region is different from surroundings, thereby causing deviation of an ejecting direction (slippage).
Fundamentally, the deposit is generally present in a trace amount (layer thickness of deposit: at most 1 im) and dissolved in inks, but may appear in some cases when a case where an ink-jet recording apparatus is left to stand in a dry environment or under conditions that the temperature is rapidly changed in a short period of time like in a heat cycle test is combined with a case where an ink droplet (at most 20 ng) having small kinetic energy is ejected. Namely, it has been found that components derived from various kinds of additives contained in a fibrous material as a product and treatment oils applied at a production stage are released into an ink upon contact with the ink, and a failure in ink ejection is caused by this.
In particular, a spinning oil and a finishing oil, which are applied as a lubricant, antistatic agent and the like to fiber during a production step of the fiber, contain an oily component and a surfactant in a mixed state, and moreover a neutralizer having a function to neutralize a residue in a polymerization catalyst, stabilizers or compatibilizers including an antioxidant, a lubricant, and the like are also added into a starting resin. When these substances are released into an ink, these move in the form of solutes having a low solubility or suspended matter together with the ink to form a deposit layer such as an oil film on an ejection opening face of an ink-jet head and remain there, thereby impairing the water repellency of the ejection opening face, which forms the cause that a failure in ink ejection is caused.
The present inventors have found that the above-described problems can be solved by using a specific treating agent to remove, or dissolve or emulsify such dissolving-out components in advance.
It is an object of the present invention to provide a fibrous material from which a member such as a not-expensive and high-performance ink-absorbing member, with which a liquid comes into contact, can be produced, and a production process thereof
Another object of the present invention is to provide a member such as a not-expensive and high-performance ink-absorbing member, with which a liquid comes into contact, and a production process thereof.
A further object of the present invention is to provide a fibrous material in which the content of component (hereinafter may be referred to as xe2x80x9creleasable componentxe2x80x9d), which is to be possibly released into an ink and forms the cause of a failure in ink ejection from an ink-jet head, is effectively held down, a member such as an ink-absorbing member, with which a liquid comes into contact, composed of the fibrous material, and production processes thereof.
A still further object of the present invention is to provide an ink-absorbing member which functions as a member for ink-jet and can be used in the production of an ink tank having a structure suitable for recycle, and a production process thereof.
Yet still a further object of the present invention is to provide an ink tank having a structure suitable for recycle, and an ink-jet apparatus using the ink tank.
The above objects can be achieved by the present invention described below.
In one aspect of the present invention, there is thus provided a process for producing a fibrous material for a member with which an ink-jet ink comes into contact, including the step of melt spinning a thermoplastic resin, the process comprising the step of: subjecting a spun yarn to a glycol treatment in which the spun yarn is contacted with a glycol added with ethylene oxide.
In another aspect of the present invention, there is also provided a fibrous material produced in accordance with the production process described above.
In a further aspect of the present invention, there is provided a fibrous material composed of a thermoplastic resin, to which a glycol added with ethylene oxide is applied.
In still a further aspect of the present invention, there is provided a fibrous material composed of a thermoplastic resin, wherein an amount released upon contact with an ink-jet ink of releasable components derived from treating oils, which are to be possibly released into the ink-jet ink, is at most 100 ppm based on the weight of the ink.
In yet another aspect of the present invention, there is provided an ink-absorbing member which can deliverably hold an ink-jet ink therein, wherein the member is composed principally of one of the fibrous materials described above.
In yet still a further aspect of the present invention, there is provided a process for treating an ink-absorbing member which can deliverably hold an ink-jet ink therein, the process comprising the steps of:
treating a molding comprising a fibrous material composed of a thermoplastic resin with a treating agent containing a glycol added with ethylene oxide.
In yet still a further aspect of the present invention, there is provided an ink-absorbing member treated in accordance with the treatment process described above.
In yet still a further aspect of the present invention, there is provided an ink-absorbing member which comprises a fibrous material composed of a thermoplastic resin and can deliverably hold an ink-jet ink therein, wherein an amount released upon contact with an inkjet ink of releasable components derived from treatment oils attached to the fibrous material, which are to be possibly released into the ink-jet ink, is at most 100 ppm based on the weight of the ink.
In yet still a further aspect of the present invention, there is provided an ink tank container for ink-jet head comprising an ink chamber having an opening part communicating with the air and an ink feed opening connected to the ink-jet head, wherein one of the ink-absorbing members described above is fitted within a region including the ink feed opening in the ink chamber.
In yet still a further aspect of the present invention, there is provided an ink tank container for ink-jet head comprising an ink chamber having an opening part communicating with the air, and a connecting chamber for head, which communicates with the ink chamber and is adapted to feed an ink from the ink chamber to an ink-jet head through a connecting opening to the ink-jet head, wherein one of the ink-absorbing members described above is fitted within the connecting chamber for head.
In yet still a further aspect of the present invention, there is provided an ink tank in which an ink-jet ink is charged into the ink chamber of the ink tank container described above.
In yet still a further aspect of the present invention, there is provided an ink-jet cartridge comprising the ink tank described above and an ink-jet head for ejecting an ink contained in the ink tank on a recording medium to conduct recording.
In yet still a further aspect of the present invention, there is provided an ink-jet apparatus comprising the ink-jet cartridge described above and a carriage on which the ink-jet cartridge is detachably mounted.
In yet still a further aspect of the present invention, there is provided a treating process for regenerating an ink-absorbing member for ink-jet composed principally of a fibrous material, the process comprising the step of:
treating the ink-absorbing member with a residual ink held therein with a treating agent containing a glycol added with ethylene oxide.